Prior art includes the three patents described below;
1. Washbasin, U.S. Pat. No 679,882 by Bunting. This washbasin features a stopper with a vertical plate mounted inside a fixed sleeve. The stopper is lowered (closed) and raised (opened) by a push rod which is inserted into an inclined slot in the vertical plate. The push rod is operated by a crank which is revolved by a vertical plunger rod.
2. Fitting, U.S. Pat. No. 1,848,521 by Fleck. This washbasin features a sleeve and stopper which are raised and lowered by a lever which is operated by a vertical screw rod.
3. Waste And Overflow Fitting, U.S. Pat. No. 2,697,840 by Steele. This fitting features a horizontal shaft with a raised knuckle bend which engages a horizontal slot in a tubular valve. The valve is raised and lowered by revolving the shaft.